Template: convert negative to positive

Configuration
1

I’m trying to get Alexa to set the volume on my Denon receiver. Problem is that the receiver is showing negative dB values as display value and the component works with a positive value. Also it is scaled. I found out how to convert it, but after conversion I’m having a negative float, which should just be converted to a positive float.
So I tried it with abs() and multiplying with -1, but both return not the expected result. Was hoping someone here sees my mistake.

action:
  service: media_player.volume_set
  data_template:
    entity_id: media_player.denon_livingroom
    volume_level: '{{ Volume |float / 100 + -0.8 | round(2) }}'
speech:
  type: plaintext
  text: Ok

Volume is the var coming in through Alexa, confirmed working. Say in this example the outcome is -0.50, and it needs to be 0.50. Shouldn’t be a problem;

{{ Volume |float / 100 + -0.8 | round(2) | abs }}

And instead of the expected 0.50 it returns 1.1.
If I multiply with -1, it also returns 1.1

I think it has something to do with order, but using parentheses isn’t possible in Jinja2, right?

2

You are partially right. This is order of operations.
In this case, you are sending -.08 to the Round(2) filter.
BUT you are wrong that parenthesis are not allowed. You absolutely can do something like :

{{ (Volume |float / 100 + -0.8) | round(2) | abs }}

I can’t make out from your problem statement if this is the right way to structure your formula, but the point is you can change the order of operations with parens.

1 Like
3

You’re the man! :smile:
I didn’t open the parenthesis including the variable but starting at float and that’s what got me the error.

This works as expected!
Thanks.